A conventional cellular phone has a display device long in the vertical direction. A digital video image having a portrait format is displayed on the display device. In recent years, a variety of digital video images to be displayed are increasing. To cope with this, a technique for displaying a digital video image having a landscape format on a display device long in the vertical direction in an easily observable manner has been examined. For example, Japanese Patent Laid-Open No. 2002-108757 (Reference 1) has proposed a server apparatus. When the screen of a cellular phone is long in the vertical direction, the server apparatus rotates a digital video image having a landscape format by 90° and distributes it to the cellular phone.
In the technique described in the Reference 1, however, the digital video image must be rotated by 90° in the server apparatus. Hence, the load on the server apparatus is heavy. This problem becomes more serious as the number of portable devices that access the server apparatus increases.
Although the technique described in the Reference 1 can improve display of a digital video image having a landscape format, a method of displaying other display information such as information to be sent to the user (e.g., information about the cellular phone or information about an image) is not taken into consideration. For this reason, even when a digital video image having a landscape format is rotated by 90° and displayed, information to be sent to the user may be displayed without being rotated by 90°. In this case, the direction of the digital video image is different from that of the information to be sent to the user. Hence, it is not easy to see the information to be sent to the user.
Additionally, in the technique described in the Reference 1, the user of a cellular phone cannot select the direction of rotation of a digital video image having a landscape format.